Diesel light oil composition

ABSTRACT

To provide a diesel light oil composition having an excellent ignitability while containing butanol. The diesel light oil composition comprises a diesel light oil base material, butanol having a volume percentage in a range of 9% to 20% and butyl nitrate or butyl nitrite having a volume percentage in a range of 0.8% to 4%. It is preferable that the butanol is 20 v/v %, and the butyl nitrate or butyl nitrite is 4 v/v %. The butyl nitrite or butyl nitrate is derived from butanol as a material.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a diesel light oil composition.

2. Description of the Related Art

In recent years, it has been demanded to reduce the discharged amount of carbon dioxide for the purpose of preventing the global warming, and various means to reduce the discharged amount of carbon dioxide have been proposed. As one of such means, it is known to use ethanol, butanol or the like obtained by fermentation and distillation of botanical materials, for example, agricultural crops such as sugar cane and corn as fuels or the like for vehicles.

Carbon contained in the botanical materials comes from atmospheric carbon dioxide which has been absorbed through photosynthesis by plants serving as raw materials. Therefore, the amount of carbon dioxide discharged upon combustion of the botanical materials is equal to the amount of carbon dioxide which has been absorbed by the plants, and as a result, the discharged amount of carbon dioxide in total is theoretically zero (carbon neutral effect). Accordingly, it is known to mix and use ethanol, which is one of the botanical materials mentioned above, with gasoline as a fuel for a gasoline engine (see Japanese Patent Laid-Open Publication No. 2005-29761).

In the meantime, there is a diesel engine as an internal combustion engine which is capable of reducing fuel cost and discharged substances. The diesel engine is driven by compression self-ignition of a fuel such as diesel light oil, and it is known that the diesel engine discharges small amount of carbon dioxide. Meanwhile, butanol, which is also one of the botanical materials mentioned above, has advantages over ethanol such as: 1) butanol can be mixed with a hydrocarbon fuel in an arbitrary ratio; 2) butanol does not cause phase separation with water; 3) butanol has a high calorific value per unit volume; and 4) butanol has a lower vapor pressure and therefore requires no measures for coping with vapor pressure. Accordingly, it is supposed that if butanol can be mixed in the diesel light oil, further advantages can be attained from the aspect of reducing the discharged amount of carbon dioxide.

However, since butanol has a low ignitability, there is a disadvantage that a fuel in which butanol is mixed in the diesel light oil has also deteriorated ignitability.

SUMMARY OF THE INVENTION

The present invention has been accomplished in view of the aforementioned problems, and it is therefore an objective of the present invention to provide a diesel light oil composition having an excellent ignitability while containing butanol therein.

To achieve the objective of the present invention, the diesel light oil composition of the present invention is a diesel light oil composition comprising a diesel light oil base material, butanol having a volume percentage in a range of 9% to 20% and butyl nitrate or butyl nitrite having a volume percentage in a range of 0.8% to 4%.

The diesel light oil composition of the present invention enables to attain an excellent ignitability despite of containing butanol therein by containing butyl nitrite or butyl nitrate in the above described range along with butanol in the above described range.

In the diesel light oil composition of the present invention, when the butanol mentioned above is a botanical material obtained by fermentation and distillation of agricultural crops, for example, sugar cane, corn or the like, discharged amount of carbon dioxide due to the butanol can be considered to be zero owing to the carbon neutral effect, and as a result, the discharged amount of carbon dioxide can be reduced.

When the content of the butanol is less than 9 v/v %, no effect of reducing the discharged amount of carbon dioxide is attained, and when the content of the butanol exceeds 20 v/v %, the ignitability in the diesel engine is degraded, and decrease in the output power is also caused due to decrease in the calorific value per unit volume.

When the content of the butyl nitrite or butyl nitrate is less than 0.8 v/v %, the ignitability of the diesel light oil composition containing butanol cannot be improved, and when the content of the butyl nitrite or butyl nitrate exceeds 4 v/v %, no further effect can be attained.

It is known that an alkyl nitrate having 6 or 8 carbon atoms is used as a cetane number improver to improve the ignitability of diesel light oil (see Japanese Patent No. 3102934), but it has not been known that butyl nitrite or butyl nitrate is used as such a cetane number improver.

In the diesel light oil composition of the present invention, the butyl nitrite or butyl nitrate may be synthesized through any kind of reaction path, but those derived from butanol as a raw material are preferable. According to the diesel light oil composition of the present invention, the butyl nitrite or butyl nitrate can not only improve the ignitability of the diesel light oil composition containing butanol, but also contribute to the reduction on the discharged amount of carbon dioxide along with butanol when butanol is used as a raw material.

When butanol is used as a raw material, the butyl nitrite can be obtained from the reaction between butanol and nitrous acid, and the butyl nitrate can be obtained from the reaction between butanol and nitric acid.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, an embodiment of the present invention is described in more detail.

The diesel light oil composition of the present embodiment contains a diesel light oil base material, butanol having a volume percentage in a range of 9% to 20% and butyl nitrite or butyl nitrate having a volume percentage in a range of 0.8% to 4%.

The butanol may be synthesized industrially, but is preferably derived from plants serving as raw materials from the viewpoint of reducing the discharged amount of carbon dioxide. Examples of butanol derived from plants serving as raw materials may include, for example, butanol obtained by fermentation and distillation of agricultural crops such as sugarcane and corn.

The butyl nitrite or butyl nitrate may be synthesized through any type of reaction path, but is preferably derived from butanol serving as a raw material from the viewpoint of reducing the discharged amount of carbon dioxide.

When butanol is used as a raw material, the butyl nitrite can be obtained by the reaction of butanol with nitrogen monoxide and oxygen as shown in the following formula (1):

C₄H₉OH+NO+¼O₂→C₄H₉ONO+½H₂O   (1)

The butyl nitrite can be also obtained by the reactions between butanol and nitrous acid salts as shown in the following formulas (2) and (3):

C₄H₉OH+NaNO₂→C₄H₉ONO+NaOH   (2)

C₄H₉OH+KNO₂→C₄H₉ONO+KOH   (3)

In addition, the butyl nitrite can also be obtained by the reaction between butanol and nitric acid using a platinum catalyst and the reaction of butanol with carbon dioxide hydrate nitrogen and oxygen.

On the other hand, when butanol is used as a raw material, the butyl nitrate can be obtained by the reaction of butanol with nitric acid using sulfuric acid as a catalyst as shown in the following formula (4):

C₄H₉OH+HNO₃→C₄H₉ONO₂+H₂O   (4)

The butyl nitrate can be also obtained by the reaction between butanol and acetyl nitrate as shown in the following formula (5).

C₄H₉OH+CH₃COONO₂→C₄H₉ONO₂+CH₃COOH   (5)

In addition, the butyl nitrate can be also obtained by the reaction between sulfonated butanol and a quaternary organic ammonium nitrate salt as shown in the following formulas (6) and (7).

C₄H₉OH+CH₃SO₃H→C₄H₉OSO₂CH₃+H₂O   (6)

C₄H₉OSO₂CH₃+(CH₃)₄N⁺NO₃ ⁻→C₄H₉ONO₂+(CH₃)₄N⁺(OSO₂CH₃)⁻  (7)

Hereinbelow, examples of the present invention and comparative examples are described.

EXAMPLE 1

In this Example, a diesel light oil composition containing 90 v % of commercial light oil as the diesel light oil base material and 10 v % of butanol and 1 v % of butyl nitrite with respect to the total volume of the commercial light oil and butanol was prepared at first. That is, the diesel light oil composition of this Example contains 9.9 v/v % butanol and 0.99 v/v % butyl nitrite with respect to the total volume of the diesel light oil composition. In addition, the butanol is derived from plants serving as raw materials, and the butyl nitrite is derived from the butanol as a raw material.

Next, the ignitability of the obtained diesel light oil composition was tested. The ignitability test was carried out by using a fuel spray ignition analyzer (tradename: FIA-100; manufactured by Fuel Tech, Inc.) equipped with a fuel pressurizing device under the settings of a combustion chamber at a temperature of 500° C., a fuel injection pressure of 100 MPa and a pressure inside the combustion chamber of 2 MPa and measuring the time period from the time point when the valve was opened to the time point when the pressure in the combustion chamber increased by 0.02 MPa by observing the signal of the needle lift sensor of the injector (hereinbelow referred to as ignition delay time) when a fuel was sprayed and ignited to combustion in the thermoregulatable combustion chamber. The results are shown in Table 1.

Then, the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Example was calculated. Here, the discharged amount of carbon dioxide from butanol and butyl nitrite was assumed to be zero owing to the carbon neutral effect. The results are shown in Table 1.

As a contrast, the ignitability of diesel light oil containing of 100 v % of commercial light oil was tested in the same manner as in Example 1 and the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this contrast was calculated. The results are shown in Table 1.

EXAMPLE 2

Next, a diesel light oil composition containing of 90 v % of commercial light oil as the diesel light oil base material and 10 v % of butanol and 2 v % of butyl nitrite to the total of the commercial light oil and butanol was prepared. That is, the diesel light oil composition of this Example contains butanol in 9.8 v/v % and butyl nitrite in 2.0 v/v % with respect to the total volume of the diesel light oil composition.

Then, the ignitability of the diesel light oil composition prepared in this Example was tested totally in the same manner as in Example 1 and the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Example was calculated. The results are shown in Table 1.

EXAMPLE 3

In this Example, a diesel light oil composition containing 80 v % of commercial light oil as the diesel light oil base material and 20 v % of butanol and 4 v % of butyl nitrite to the total of the commercial light oil and butanol was prepared. That is, the diesel light oil composition of this Example contains butanol in 19.2 v/v % and butyl nitrite in 3.8 v/v % with respect to the total volume of the diesel light oil composition.

Then, the ignitability of the diesel light oil composition prepared in this Example was tested totally in the same manner as in Example 1 and the discharged amount carbon dioxide per calorific value in the diesel light oil composition of this Example was calculated. The results are shown in Table 1.

EXAMPLE 4

In this Example, a diesel light oil composition containing 90 v % of commercial light oil as the diesel light oil base material and 10 v % of butanol and 1 v % of butyl nitrate to the total of the commercial light oil and butanol was prepared. That is, the diesel light oil composition of this Example contains butanol in 9.9 v/v % and butyl nitrate in 0.99 v/v % with respect to the total volume of the diesel light oil composition. Here, the butyl nitrate is derived from the butanol as a raw material and the butanol is derived from plants serving as raw materials.

Then, the ignitability of the diesel light oil composition prepared in this Example was tested totally in the same manner as in Example 1 and the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Example was calculated. Here, the discharged amount of carbon dioxide due to butyl nitrate was assumed to be zero owing to the carbon neutral effect. The results are shown in Table 1.

EXAMPLE 5

Next, a diesel light oil composition containing of 80 v % of commercial light oil as the diesel light oil base material and 20 v % of butanol and 4 v % of butyl nitrate to the total of the commercial light oil and butanol was prepared. That is, the diesel light oil composition of this Example contains butanol in 19.2 v/v % and butyl nitrate in 3.8 v/v % with respect to the total volume of the diesel light oil composition.

Then, the ignitability of the diesel light oil composition prepared in this Example was tested totally in the same manner as in Example 1 and the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Example was calculated. Here, the discharged amount of carbon dioxide due to butyl nitrate was assumed to be zero owing to the carbon neutral effect. The results are shown in Table 1.

COMPARATIVE EXAMPLE 1

In this Comparative example, a diesel light oil composition containing of 90 v % of commercial light oil as the diesel light oil base material and 10 v % of butanol was prepared.

Then, the ignitability of the diesel light oil composition prepared in this Comparative example was tested totally in the same manner as in Example 1 and the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Comparative example was calculated. The results are shown in Table 1.

COMPARATIVE EXAMPLE 2

In this Comparative example, a diesel light oil composition containing of 80 v % of commercial light oil as the diesel light oil base material and 20 v % of butanol was prepared.

Then, the ignitability of the diesel light oil composition prepared in this Comparative example was tested totally in the same manner as in Example 1 and the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Comparative example was calculated. The results are shown in Table 1.

COMPARATIVE EXAMPLE 3

In this Comparative example, a diesel light oil composition containing of 90 v % of commercial light oil as the diesel light oil base material and 10 v % of butanol and 1 v % of di-tert-butylhydroperoxide (hereinbelow referred to as DTBP) to the total of the commercial light oil and butanol was prepared. That is, the diesel light oil composition of this Comparative example contains butanol in 9.9 v/v % and DTBP in 0.99 v/v % with respect to the total volume of the diesel light oil composition. Here, the DTBP is derived from petroleum.

Then, the ignitability of the diesel light oil composition prepared in this Comparative example was tested totally in the same manner as in Example 1 and the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Comparative example was calculated. Here, since DTBP is derived from petroleum, the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Comparative example is a value to which the discharged amount of carbon dioxide due to DTBP has been added. The results are shown in Table 1.

COMPARATIVE EXAMPLE 4

In this Comparative example, a diesel light oil composition containing 90 v % of commercial light oil as the diesel light oil base material and 10 v % of butanol and 2 v % of DTBP to the total of the commercial light oil and butanol was prepared. That is, the diesel light oil composition of this Comparative example contains butanol in 9.8 v/v % and DTBP in 2.0 v/v % with respect to the total volume of the diesel light oil composition.

Then, the ignitability of the diesel light oil composition prepared in this Comparative example was tested totally in the same manner as in Example 1 and the discharged amount of carbon dioxide per calorific value in the diesel light oil composition of this Comparative example was calculated. The results are shown in Table 1.

TABLE 1 Commercial Butyl Butyl Ignition CO₂/calorific light oil Butanol nitrite nitrate DTBP delay time value (v %) (v %) (v %)* (v %)* (v %)* (ms) (g/kJ) Contrast 100 — — — — 4.57 70.9 Example 1 90 10 1 — — 4.51 65.4 Example 2 90 10 2 — — 4.03 65.0 Example 3 80 20 4 — — 4.50 58.7 Example 4 90 10 — 1 — 4.55 65.5 Example 5 80 20 — 4 — 4.56 59.1 Comparative1 90 10 — — — 5.11 65.8 Comparative2 80 20 — — — 6.08 60.2 Comparative3 90 10 — — 1 4.55 65.8 Comparative4 90 10 — — 2 4.14 65.9 *The ratios of butyl nitrite, butyl nitrate and DTBP are v % with respect to the total volume of commercial light oil and butanol.

It has been clearly shown from Table 1 that the diesel light oil compositions of Comparative example 1 and Comparative example 2 containing commercial light oil and butanol have a longer ignition delay time than the diesel light oil of the contrast containing 100 v/v % of commercial light oil, which means that the ignitability is deteriorated.

On the other hand, it has been clearly shown that the diesel light oil compositions of Examples 1 to 5 containing commercial light oil and butanol and butyl nitrite or butyl nitrate have a shorter ignition delay time than the diesel light oil of the contrast, which means that the ignitability is enhanced, and that the the discharged amount of carbon dioxide per calorific value of Examples 1 to 5 is lower than that of the diesel light oil composition of the contrast, and those of the diesel light oil compositions of Comparative examples 3 and 4 containing commercial light oil and butanol and DTBP.

Therefore, it has been clearly shown that the diesel light oil compositions of Examples 1 to 5 have a shorter ignition delay time and an excellent ignitability, and besides, they are small in the discharged amount of carbon dioxide per calorific value and therefore effective for the reduction of the the discharged amount of carbon dioxide. 

1. A diesel light oil composition comprising a diesel light oil base material, butanol having a volume percentage in a range of 9% to 20%, and butyl nitrate having a volume percentage in a range of 0.8% to 4%.
 2. The diesel light oil composition according to claim 1, wherein the butanol is 20 v/v % and the butyl nitrate is 4 v/v %.
 3. The diesel light oil composition according to claim 1, wherein the butyl nitrate is derived from butanol.
 4. A diesel light oil composition comprising a diesel light oil base material, butanol having a volume percentage in a range of 9% to 20%, and butyl nitrite having a volume percentage in a range of 0.8% to 4%.
 5. The diesel light oil composition according to claim 4, wherein the butanol is 20 v/v % and the butyl nitrite is 4 v/v %.
 6. The diesel light oil composition of claim 4, wherein the butyl nitrite is derived from butanol.
 7. The diesel light oil composition according to claim 2, wherein the butyl nitrate is derived from butanol.
 8. The diesel light oil composition of claim 5, wherein the butyl nitrite is derived from butanol. 